Improvement in steam and cut-off valves



UNITED STATES PATENT ETICEO ELBERT E. GROOM()F NEW YORK, N. Y.

IMPROVEMENT IN STEAM AND CUT-OFF VALVES.

` To all whom if may concern:

Be it known that I, GROOM, of the city, county, and State ot' New York, haveinvented a new and Improved Steam and OutiOff Valve; and I do hereby declare that the following is a full, clear, and exact description ithereot, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming la part ot' this specication, in which- Figure l represents a side elevation of this invention. Fig. 2 is a plan or top view of the l same, the cover ofthe valve-chest having been removed to show the position ot' the valves. Fig. 3 is a transverse vertical section ot' the ,same, the line m Fig. 2, indicating the plane `lot" section. Fig. 411s a detached end view of the valve-chest cover.

Similar letters oi' reference indicate like parts.

This invention refers to the use ot' a double ,piston-valve, each piston being provided with `a cavity between its ends to operate in combi- 11ation with steam supply and exhaust ports,

in the same manner as an ordinary .D--valve, steam being admitted through the cavities in lthe piston to the steam-ports, while said cavij ties serve also t o form the communication beltween the steam and exhaust ports, and small recesses extending from said cavities allow the fsteam to pass clear round the central portions i ofthe piston-valves, rendering the same equally balanced and independent of the pressure of steam in which they act.

, In order to balance the piston-valves from ,the ends in case one should leak the steamichest cover is provided with a channel which l serves to equalize the pressure on the ends of l the piston-valves. These balanced double piston-valves are combined with a cut-off valve 1 composed of two pistons which are subjected to i the action of aspring and of an adjustable tripfping device. The spring acts by two hooked rods on a double-slotted toothed segment which Jgears in a toothed rack secured to the cut-oft'.- valve rod, in such a manner that in whatever ydirection the toothed segment will be turned `the spring has a tendency to carry it back to jits original position and to hold it there, and consequently if the valve is opened immedig ately upon being released it will close and stay `closed until it is disturbed in its position by some external force.

The tripping` device consists of two latches hinged to the upper edge of the toothed rack, in combination with a tappet-lever to which a reciprocating motion is imparted by a rockerarm or other suitable means, and which is suspended from a lever which is adj usted l,either by hand or by the governor, in such a manner that by the action ot' said tappet-lever on the hinged latches the cutoff valve is carried along in either direction and tripped at the vdesired point, according to the position ot' the adjustable lever from which saidv tappet-lever is suspended.

A represents a steam cylinder, to which steam is admitted through ports a a', and from which the steam exhausts through said ports a a and through the exhaust-ports b b'. The ports a a b b are situated in thebottom of the compartment o of the steam-chest B, as shown in Fig.'2 ot' the drawings, and the ports a a pass through the .partition d to the compartment e of said steam-chest, to which steam is admitted through the steam-pipe C.

The compartments c e ot' the steam-chest are bored out circular to receive the piston-valves D E, the valves D to represent the exhaustvalve, and the valves E the cut-ott' valve, of the engine.

The valves D connect by the rod f with the rocker-arm F, to which a vibrating motion is imparted by an eccentric on the crank-shaft or by any other suitable mechanism, and each of said valves is provided with a cavity, g, at its under side, (see Fig. 3,) so that when said cavity comes over the ports a b or a `b', a communication is effected between the exhaustport and the interior of the cylinder, and the steam is free to discharge. The cavities g are situated between the packed ends ot the pistons D, which lit' steam-tight into their compartment of the steam-chest, and they communicate with shallow recesses g', extending round the upper parts ot the pistons, so that the steam is permitted to pass clear round and veach piston is perfectly balanced and rendered independent of the pressure of the steam to which it may be exposed.

i In order' to balance the piston-valves D from the ends, in case one of said pistons should leak, a channel, h, extends through the whole length of the steam-chest cover, as shown in Figs. 3 and 4. This channel communicates at both ends with both compartments of the steam-chest, and consequently the pressure of the steam acting on the ends of the several piston-valves is equally balanced.

The communication between the steam-pipe C and the ports a a is opened and closed by the action ofthe cut-oft' valves E. These valves are made in the form of pistons, as previously stated, and they work in the compartment e of the steam-chest. Their posit-ion is governed by the action ot' a tripping device, which is constructed as follows: The rod j, on which the piston-valves E are mounted, terminates in a toothed rack, k, which gears in the cogsgof a segment or disk, Z, and this disk is provided with two slots, m' fm', from each of which eX- tends a hooked rod, a or n', to a spiral spring, o, which is secured to the bed-plate of the engine or to any convenient spot.` The spring o and the rods n u are so arranged that the same have atendency to keep the disk lin a central position-or, in oth er words,ir1 such a position in which the same causes the valve E to close the steam-ports (L onf-and whenever said disk is disturbed from its central position it will iiy back immediately upon being` released and cause the steam-ports to be closed.

The cut-oft' valves are opened by the action of a tappetpp, secured to the end of a lever, which is pivoted to the`rocker-arm F, or to which motion is imparted in any covenient manner. This tappet is suspended from the bed ofthe engineer secured to any other convenient place, and it extends into a recess, i,

formed between the ends oi" two latches, s s', l

can be made to trip the cut-off valves sooner or later, according to the time when it is desired to cut off the steam. Said lever may either be adjusted by hand, or it may be connected to the governor, so that the cnt-ofi is rendered self-adjusting. The principal advantage of this tripping mechanism is that the spring o, which is the principal agent of the same, is not liable to lose its power, since what it loses von one side it gains on the other. At the same time it must be remarked that said spring might be replaced by a simple weight. By such spring or weight the cut-od' valve is securely closed whenever the tappet releases the latches on the top edge of the rack.

I claim as new and desire to secure by Letters Patentl. The cavities g, and shallow recesses g, in the piston-valves D, adapted to operate in conjunction with the ports a et b b', in the manner and for the purpose specified.

2. The channel h, in the steam-chest cover, in combination with'the double piston-valves D E, constructed and operating substantially as and for the purpose specified.

3. The tappet p, suspended from the adjustable lever g, in combination with the hinged latches s s', toothed rack 7c, disk l, and spring o, or its equivalent, constructed and operating substantially as and for the purpose set forth.

The above specification ot my invention signed by me this 25th daybf August, 1865.

ELBERT E. GROOM.

Witnesses:

M. M. LIVINGSTON, C. L. ToPLIFF. 

